Actually, at large defense contractors there is significant pressure not to bill more than 40 hours per week. It (theoretically) keeps costs down and makes the contractor more appealing for future work. It skews the actuals all to hell, though, because on paper it looks like a project took X hours when it actually took 1.2X hours because everyone was working an average of 48 hours a week but only billing 40. In some cases it can skew even worse. I had a couple workaholic co-workers who regularly put in 25+ unpaid extra hours.
The government doesn't particularly like this, but they usually don't clamp down on the practice. They do get upset when contractors knowingly distort their bids with estimates of this, though. Marietta, before they got rolled up into Lockheed Martin via mergers, once got in trouble because they submitted a bid wherein they assumed "full-time" would be 43 hours per week and set their time projections accordingly. The government auditors were pissed when they found out.
The government doesn't particularly like this, but they usually don't clamp down on the practice. They do get upset when contractors knowingly distort their bids with estimates of this, though. Marietta, before they got rolled up into Lockheed Martin via mergers, once got in trouble because they submitted a bid wherein they assumed "full-time" would be 43 hours per week and set their time projections accordingly. The government auditors were pissed when they found out.